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dcb.h

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-------
Removed DCB states DCB_STATE_IDLE, and DCB_STATE_PROCESSING.
Added DCB_STATE_UNDEFINED for initial content for state variable which doesn't have any specific value set, and DCB_STATE_NOPOLLING to indicate that dcb has been removed from poll set.

Added following dcb roles: DCB_ROLE_SERVICE_LISTENER for listeners of services, and DCB_ROLE_REQUEST_HANDLER for client/backend dcbs. Listeners may have state DCB_STATE_LISTENING, but not DCB_STATE_POLLING. Request handlers may have DCB_STATE_POLLING but not DCB_STATE_LISTENING. Role is passed as an argument to dcb.c:dcb_alloc.

From now on, struct check numbers of DCB are included and checked in DEBUG build only.

Added dcb_role_t dcb_role-member to DCB as well as SPINLOCK dcb_initlock, which protects state changes.

Removed extern keyword from function declarations because functions are by default externally visible if they are declared in header.

dcb.b
------
Function dcb_set_state, and dcb_set_state_nomutex provide functions for changing dcb states. Latter implements a state machine for dcb.
Function dcb_add_to_zombieslist replaces dcb_free. It adds in atomic step dcb to zombieslist and changes state to DCB_STATE_ZOMBIE.
Function dcb_final_free removes dcb from allDCBs list, terminates router and client sessions, and frees dcb and related memory.
Function dcb_process_zombies removes executing thread from dcb's bitmask, and it there are no further thread bits, moves dcb to a victim list, and finally, for each dcb on victim list, closes fd and sets state to DCB_STATE_DISCONNECTED.
Function dcb_close sets dcb state to DCB_STATE_NOPOLLIN, removes dcb from poll set and sets bit to bitmask for each server thread in an atomic step.  

poll.c
------
Function poll_add_dcb sets either DCB_STATE_LISTENING or DCB_STATE_POLLING state for newly created dcb, depending whether the role of dcb is DCB_ROLE_SERVICE_LISTENER, or DCB_ROLE_REQUEST_HANDLER, respectively. Then dcb is set to poll set.

poll_waitevents : commented out code which skipped event if dcb was added to zombieslist or if fd was closed. Added state checks.

service.c : Minor changes.
httpd.c : Removed dcb state changes. They are done in core.
mysql_backend.c : Added checks, removed dcb state changes.
mysql_client.c : Removed dcb state changes. Added checks.
mysql_common.c : Minor changes
telnetd.c : Removed state changes. Replaced some typecasts and pointer references with local variable reads.
skygw_debug.h : Removed two states, and added two to state printing macro.
This commit is contained in:
vraatikka
2013-09-05 22:00:02 +03:00
parent 17ec98fa3d
commit 66e9be814b
10 changed files with 576 additions and 384 deletions
Download Patch File Download Diff File Expand all files Collapse all files

141
server/modules/protocol/mysql_client.c
View File

@ -510,22 +510,9 @@ int gw_read_client_event(DCB* dcb) {
MySQLProtocol *protocol = NULL;
int b = -1;
int rc = 0;
#if 0
dcb->state = dcb_begin_action(dcb, DCB_ACTION_READ);
#else
CHK_DCB(dcb);
if (dcb->state == DCB_STATE_DISCONNECTED ||
dcb->state == DCB_STATE_FREED ||
dcb->state == DCB_STATE_ZOMBIE ||
dcb->state == DCB_STATE_PROCESSING)
{
rc = 1;
goto return_rc;
}
ss_dassert(dcb->state == DCB_STATE_POLLING);
dcb->state = DCB_STATE_PROCESSING;
#endif
protocol = DCB_PROTOCOL(dcb, MySQLProtocol);
CHK_PROTOCOL(protocol);
/**
@ -647,9 +634,9 @@ int gw_read_client_event(DCB* dcb) {
if (ptr_buff) {
mysql_command = ptr_buff[4];
}
if (mysql_command == '\x03') {
/// this is a standard MySQL query !!!!
/* this is a standard MySQL query !!!! */
}
/**
* Routing Client input to Backend
@ -657,24 +644,20 @@ int gw_read_client_event(DCB* dcb) {
/* Do not route the query without session! */
if(rsession == NULL) {
if (mysql_command == '\x01') {
/* COM_QUIT handling */
/* fprintf(stderr, "COM_QUIT received with
* no connected backends from %i\n", dcb->fd); */
/**
* COM_QUIT handling
*
* fprintf(stderr, "COM_QUIT received with
* no connected backends from %i\n", dcb->fd);
*/
(dcb->func).close(dcb);
} else {
/* Send a custom error as MySQL command reply */
if (dcb) {
mysql_send_custom_error(
dcb,
1,
0,
"Connection to backend lost");
} else {
skygw_log_write(
LOGFILE_ERROR,
"%lu [mysql_send_custom_error] client dcb is NULL.",
pthread_self());
}
mysql_send_custom_error(
dcb,
1,
0,
"Connection to backend lost");
protocol->state = MYSQL_IDLE;
}
rc = 1;
@ -683,19 +666,19 @@ int gw_read_client_event(DCB* dcb) {
/* We can route the query */
/* COM_QUIT handling */
if (mysql_command == '\x01') {
/* fprintf(stderr, "COM_QUIT received from %i and
* passed to backed\n", dcb->fd); */
/* this will propagate COM_QUIT to backend(s) */
//fprintf(stderr, "<<< Routing the COM_QUIT ...\n");
router->routeQuery(router_instance,
rsession,
queue);
/**
* fprintf(stderr, "COM_QUIT received from %i and
* passed to backed\n", dcb->fd);
* this will propagate COM_QUIT to backend(s)
* fprintf(stderr, "<<< Routing the COM_QUIT ...\n");
*/
router->routeQuery(router_instance, rsession, queue);
/* close client connection */
(dcb->func).close(dcb);
rc = 1;
return rc;
goto return_rc;
}
/* MySQL Command Routing */
protocol->state = MYSQL_ROUTING;
@ -715,65 +698,66 @@ int gw_read_client_event(DCB* dcb) {
rc = 0;
return_rc:
dcb->state = DCB_STATE_POLLING;
return rc;
}
///////////////////////////////////////////////
// client write event to Client triggered by EPOLLOUT
//////////////////////////////////////////////
int gw_write_client_event(DCB *dcb) {
int gw_write_client_event(DCB *dcb)
{
MySQLProtocol *protocol = NULL;
CHK_DCB(dcb);
if (dcb == NULL) {
fprintf(stderr, "DCB is NULL, return\n");
return 1;
}
ss_dassert(dcb->state != DCB_STATE_DISCONNECTED);
if (dcb->state == DCB_STATE_DISCONNECTED) {
return 1;
}
dcb->state = DCB_STATE_PROCESSING;
if (dcb->protocol) {
protocol = DCB_PROTOCOL(dcb, MySQLProtocol);
} else {
fprintf(stderr, "DCB protocol is NULL, return\n");
dcb->state = DCB_STATE_POLLING;
return 1;
goto return_1;
}
if (protocol->state == MYSQL_IDLE ||
protocol->state == MYSQL_WAITING_RESULT)
{
dcb_drain_writeq(dcb);
dcb->state = DCB_STATE_POLLING;
return 1;
goto return_1;
}
dcb->state = DCB_STATE_POLLING;
return 1;
return_1:
return 1;
}
///
// set listener for mysql protocol, retur 1 on success and 0 in failure
///
int gw_MySQLListener(DCB *listener, char *config_bind) {
/**
* set listener for mysql protocol, retur 1 on success and 0 in failure
*/
int gw_MySQLListener(
DCB *listen_dcb,
char *config_bind)
{
int l_so;
struct sockaddr_in serv_addr;
char *bind_address_and_port = NULL;
char *p;
char address[1024] = "";
int port=0;
int one = 1;
int port = 0;
int one = 1;
// this gateway, as default, will bind on port 4404 for localhost only
/* this gateway, as default, will bind on port 4404 for localhost only */
if (config_bind != NULL) {
bind_address_and_port = config_bind;
} else {
bind_address_and_port = "127.0.0.1:4406";
}
listener->fd = -1;
listen_dcb->fd = -1;
memset(&serv_addr, 0, sizeof serv_addr);
serv_addr.sin_family = AF_INET;
p = strchr(bind_address_and_port, ':');
@ -829,12 +813,11 @@ int gw_MySQLListener(DCB *listener, char *config_bind) {
fprintf(stderr,
">> GATEWAY listen backlog queue is %i\n",
10 * SOMAXCONN);
listener->state = DCB_STATE_IDLE;
// assign l_so to dcb
listener->fd = l_so;
listen_dcb->fd = l_so;
// add listening socket to poll structure
if (poll_add_dcb(listener) == -1) {
if (poll_add_dcb(listen_dcb) == -1) {
fprintf(stderr,
">>> poll_add_dcb: can't add the listen_sock! Errno "
"%i, %s\n",
@ -842,15 +825,14 @@ int gw_MySQLListener(DCB *listener, char *config_bind) {
strerror(errno));
return 0;
}
listener->func.accept = gw_MySQLAccept;
listener->state = DCB_STATE_LISTENING;
listen_dcb->func.accept = gw_MySQLAccept;
return 1;
}
int gw_MySQLAccept(DCB *listener) {
int gw_MySQLAccept(DCB *listener)
{
fprintf(stderr, "MySQL Listener socket is: %i\n", listener->fd);
while (1) {
@ -863,7 +845,9 @@ int gw_MySQLAccept(DCB *listener) {
socklen_t optlen = sizeof(sendbuf);
// new connection from client
c_sock = accept(listener->fd, (struct sockaddr *) &local, &addrlen);
c_sock = accept(listener->fd,
(struct sockaddr *) &local,
&addrlen);
if (c_sock == -1) {
if ((errno == EAGAIN) || (errno == EWOULDBLOCK)) {
@ -892,7 +876,7 @@ int gw_MySQLAccept(DCB *listener) {
setsockopt(c_sock, SOL_SOCKET, SO_SNDBUF, &sendbuf, optlen);
setnonblocking(c_sock);
client_dcb = dcb_alloc();
client_dcb = dcb_alloc(DCB_ROLE_REQUEST_HANDLER);
client_dcb->service = listener->session->service;
client_dcb->fd = c_sock;
client_dcb->remote = strdup(inet_ntoa(local.sin_addr));
@ -909,9 +893,6 @@ int gw_MySQLAccept(DCB *listener) {
}
// assign function poiters to "func" field
memcpy(&client_dcb->func, &MyObject, sizeof(GWPROTOCOL));
client_dcb->state = DCB_STATE_IDLE;
//send handshake to the client_dcb
MySQLSendHandshake(client_dcb);
@ -919,21 +900,17 @@ int gw_MySQLAccept(DCB *listener) {
protocol->state = MYSQL_AUTH_SENT;
/**
* Set new descriptor to event set. Before that
* Set new descriptor to event set. At the same time,
* change state to DCB_STATE_POLLING so that
* thread which wakes up sees correct state.
*
*/
client_dcb->state = DCB_STATE_POLLING;
if (poll_add_dcb(client_dcb) == -1)
{
/** Return to previous state. */
client_dcb->state = DCB_STATE_IDLE;
/** Previous state is recovered in poll_add_dcb. */
skygw_log_write_flush(
LOGFILE_ERROR,
"%lu [gw_MySQLAccept] Failed to add dcb %p for fd "
"%d to epoll set.",
"%lu [gw_MySQLAccept] Failed to add dcb %p for "
"fd %d to epoll set.",
pthread_self(),
client_dcb,
client_dcb->fd);
@ -957,7 +934,7 @@ int gw_MySQLAccept(DCB *listener) {
*/
static int gw_error_client_event(DCB *dcb) {
//fprintf(stderr, "#### Handle error function gw_error_client_event, for [%i] is [%s]\n", dcb->fd, gw_dcb_state2string(dcb->state));
//dcb_close(dcb);
dcb_close(dcb);
return 1;
}